Contact John Kelly. He had/has it.
but then its a big difference between that and a Prowler!
The Prowler will fit in a lighter weight van, as will the new machine from Hydramaster/Solutions in Cornwall.
The White Magic will need a heftier van to ensure not overloading.
You need to consider what type of work you intend to use this machine you are obviously looking to acquire, and what your business aspirations are.
If you going big commercial, then you may consider a bigger machine.
All the domestic jobs I do I do very adequately with my 15hp Prowler and I know a 13hp would do the jobs adequately as well.